Air conditioning apparatus



y 1935- I c. A. BULKELEY 2,006,344

AIR CONDITIONING APPARATUS Filed Aug. 5, 1935 2 Sheets-Sheet l DA.'Tlzerkto. i

.RA. HyymQ INVENTOR 9.2 mi] 6 0 0 7%. KT' JRNEYS July 2, 1935- c. A.BULKELEY AIR CONDITIONING APPARATUS Filed Aug. 5; 1933 2 Sheets-Sheet 2'llllllh INVENTOR ATTORNEYS Patented July 2, 1935 UNITED STATES2,006,344 Am oounrrromu'c APPARATUS Claude A. Bulkeley, New York, N. Y.,assignor to Niagara Blower Company, New York, N. Y., a corporation ofNew York Application August 5, 1933, Serial No.683,783

8 Claims.

This invention relates to an air conditioner and more particularly to anair conditioning unit particularly adapted for domestic use or use inheating, cooling, humidifying and dehumidifying 5 small stores and thelike.

This application is a continuation in partof my co-pending applicationSerial No. 666,152, filed April 14, 1933.

One of the principal objects of this invention is to provide such adomestic air conditioning unit in which the same equipment, includingthe control equipment, and the same fan and coils can be used both forheating and humidifying during the wintertime and for cooling anddehumidifying in the summertime, thereby effecting economyininstallation.

Another purpose of the present invention is to provide such a domesticunit in which the changeover from cooling toheating and vice versa isvery easily and simply accomplished by operating only two three-way handvalves and one control switch, thereby avoiding the usual complicationsand enabling the home owner to operate the unit at all times withoutexpert assistance.

Another purpose is to provide such a unit in which the equipment isrelatively low both in first cost and operating cost, this beingparticularly important in domestic installations.

Another purpose is to provide such a unit, the component parts of whichare not new but have long been in practical use.

Another object is to provide such a unit in which the only major movingparts are the fan and cold water pump and in which the power required todrive both, even for a relatively large residence (40,000 cubic feet) isnot over one horse power. This is accomplished primarily through theunique arrangement of the coils for the passage of air and cooling orheating media.

Another aim is to provide such a system in which, when heating andhumidifying, the only moving part is the air circulating fan and inwhich the entire arrangement operates similar to any good ventilatingsystem.

Another object is to provide such a unit which avoids the necessity ofunsightly direct radiators which occupy valuable space in the room orrooms of the house.

Another object of the present invention is to provide such a unit airconditioner which can be readily installed as a heating, ventilating andhumidifying system, the dehumidifying and cooling system being omittedand, later on, this omitted cooling and dehumidifying equipment can beadded with no changes whatever in the equipment already installed and atno additional cost other than that which would have been required to putit in in the first place. 1

Another purpose of the present invention is to make the entire'unit,includingthe fan housing, 5 coils and easing of aluminum, this;eliminating any possible corrosion due to the moisture neces-.

, sarily always present in equipment of this kind.

Another object is to provide such an air conditioning system in whichthe source ofheat can 10 be any good make of steam boiler and the sourceof-cooling can be any standard well known refrigerating system, such asmelting ice or ammonia. Ammonia can be employed since the cooling wateris cooled in a shell and tube cooler 15 before passing to the coolingcoils and hence there is no chance for the refrigerant to escape intothe air stream in the event of a break in the shell and tube cooler.

Another purpose is to provide such a system 20 I 'which 'isadapted tounit construction, thereby expediting the transportation andinstallation of the equipment as well as providing equipment which ,iscompact and of neat appearance, the

In the accompanying drawings:

Fig. 1 is a diagrammatic sectional elevation of a building equipped witha domestic air conditioning unit embodying the present invention andshowing diagrammatically the arrangement and 30 action of all of. theinstrumentalities used to carry out the invention.

Fig. 2 is a diagrammatic sectional elevation through a melting icecooler suitable for use in supplying cold water when the apparatus isused 35 for cooling and dehumidifying.

Fig. 3 is a front elevation of the cooling and heating coils employedfor cooling and dehumidifying or forheating the fresh and recirculatedair delivered by the apparatus.

Fig. 4 is a horizontal section taken on line 4-4,. Fig. 3.

Fig. 5 is an end elevation of the cooling and heating coils shown. inFig. 3.

Fig. 6 is a horizontal section taken on line 6-6, Fig. 3. I

Conditioned air is supplied to each of the rooms I to be conditioned ofa building 2, the rooms having doors 3 through which air can escape sothat an excess pressure is not built up in the rooms by the constantadmission of fresh air. The various rooms I of the building may or maynot each be provided with a recirculated air outlet 4 leading to acommon duct 5 leading to a chamber 6 having a plurality of recirculatedair cooling 5 latter being especially important in .domestic use. 25

andheatingcoils1. Iftheroomsarenotpr'ovided with outlet ducts therecirculation air duct 4 can draw its recirculated air from a commonhall. The recirculated room air passes through these coils and is cooledand dehumidified when as hereinafter more fully set. forth. The freshand recirculated air from the coils 1 and I is drawn past a humidlfyingspray l2, which is operative only when heating, by a fan |3 whichthoroughly mixes the fresh and recirculated air and discharges itthrough a duct l4 back into the room. In order to clean all of the airhandled by the apparatus a filter I5 is provided in the recirculationair duct 4 and a similar filter I6 is provided in the fresh'air duct 8.

The apparatus shown in Fig. 1 is shown as set for cooling anddehumidifying operation during the summertime. During such summeroperation the cooling water to the coils 1 and I0 is passed through ashell and tube cooler 20 which can be cooled in anymamier such as byammonia and the like. The outlet 2| from this cooler connects with athree-way valve '22 which, when set for summer operation;permits thiswater to flow into a pipe 23. This pipe 23 conects with the nipple 25 ofa header 26 of the recirculation air coils 1 and also connects with thenipple 21 of a header 28 of the fresh air coils Ill. A pipe 29 connectswith the nipple 36 of the other header 3| of the recirculation air coils1 and this pipe 29 contains a reverse acting diaphragm valve 32.Similarly, a pipe 33 connects with the nipple 34 of the other header 35of the fresh air coils l0 and this pipe 33 contains a reverse actingdiaphragm valve 36. The pipes 29 and 33 connect with a pipe 31, thispipe preferably having an air cook 38 at its upper end through which anyair originally in the coils or accumulating therein can be relieved. Thepipe 31 connects with the three-way valve 39 which, during summeroperation, is set to deliver the return water to a return pipe 40leading to the inlet of the circulating pump 4|. The outlet 42 from thispump connects with the cooler 28 so that the pump continuouslycirculates cooling water through-the system just described as long asthe pump 4| is in operation.

During winter operationthe heater 45 is in operation. This heater may beany good make of steam or hot water boiler and generates steam or heatsthe water which passes from its outlet 46 to a pipe 41. During winteroperation the three-way valve 39 is set to deliver the steam or water tothe pipe 31 and the steam or water passes through the pipe 33 andreverse acting diaphragm valve 36 to the header 35 of the fresh aircoils I0 and also through the pipe 29 and reverse acting diaphragm valve32 to the header 3| of the recirculated air coil 1. The condensate orcooled water from the headers 28 and 26 of the fresh and recirculatedair coils respectively passes out through the pipe 23 and during winteroperation the three-way valve 22 is set to return this condensate orwater to the return line 48 of the heater is.

During winter operation the air stream is humidified, under automaticcontrol, to the degree desired, by the humidifying spray l2. The waterfor this spray is supplied from water supply line 60 having reverseacting diaphragm valve 5|. This water is passed through a heater 52.From the heater 52 the spray water passes through line 53 to one or morespray nozzles 54 from which it is discharged in the form of finelyatomized spray. Steam or hot water to the heater 52 is supplied througha line 55 which connects with the outlet 46 from the heater 45. Thereturn from the heater 52 passes through a return line 56 to the return48 of the heater 45.

The construction of the coils 1 and I6 is best illustrated in Figs. 3-6.As shown, the headers 26 and 3| of the recirculated air coils 1 arevertically disposed and are connected by finned tubes 68 of serpentineform and each having three horizontalruns 6| and pitched bends 62, or inother words, the plane of the tubes is at an angle to the horizontal inthe direction of the air flow only, as best shown in Fig. 5. Due to thepitch of the return bends 62 of the tubes the condensate, when the coilsare used for heating, passes freely through the coil without waterlogging or water hammer. Similarly, when cooling, any air in the tubesis carried through the coils by the cooling water and can be relievedthrough the air cook 38. coils are composed of eight such serpentinetubes arranged above one another.

The fresh air coils III are constructed in a similar manner consistingof four serpentine tubes connecting the headers 28 and 35. Each of thetubes consists of five horizontal runs 63 connected by return bends 64,the retum bends being pitched downwardly toward the header 28 in thesame manner as the recirculation air tubes. I

The coils 1 and III are separated by a partition 65 which insuressegregation of the fresh and recirculated air passing through therespective fresh air and recirculated air coils. An inclined partition66 is also arranged over the fresh air coils I0 so as to cause the freshair to pass through the coils parallel with their inclination and asimilar partition 61 is arranged under the recirculated air coils 1. Thepartitions 65 and 61 also catch the condensate dripping from the coilsurface during dehumidification and drain it into the humidificationchamber.

The apparatus shown is under thermostat and hygrostat control, thethermostat being indicated at and the hygrostat at 1|. The invention isillustrated as having a pneumatic control, but it will be understoodthat an electrical control system is equally adaptablev Theseinstruments are located in the room although it will be understood thatthey could also be arranged in the air duct 4. The thermostat andhygrostat are of.

the direct and reverse acting intermediate type respectively and aresupplied with air pressure from an air pressure supply line 12. line 13from the thermostat and theoutlet line 14 from the hygrostat connectwitha double throw air switch which during summer operation is thrown inthe S position indicated in full lines. In this position theswitch 15connects the thermostat outlet line 13 with a control line 16 andconnects the hygrostat outlet line 14 with the atmosphere. The controlline 16 is connected by a line 11 with a controller 18, this controllercontrolling the motor 19 which drives the water circUJating pump 4|. Assoon as cooling is required the rising air pressure in the lines 13, 16and 11 from the thermostat 10 operates the controller 18 to start thepump 4 and hence-cooling water is circulated through the cooler and thecoils 1 and Ill under control of the reverse act- As shown, therecirculation air The outlet ing diaphragm valves 32 and 38. The line 16from the thermostat also connects with the reverse acting diaphragmvalves 32 and 36. As the room temperature rises the rising air pressurein lines 13 and 18 first opens the reverse acting diaphragm valve 38thereby permitting the cooling water to pass through the freshair coilsI0.

Under these conditions the cooling and dehumidifylng is performed on thefresh air only, and little or no cooling of the recirculated air iseffected, the recirculated air being at correct room temperature. As theroom temperature continues to rise the rising pressure in the thermostatoutlet lines 13 and 18 opens the reverse acting diaphragm valve 32. Thisopening of the reverse acting diaphragm valve permits the cooling waterto pass in increasing amounts through the recirculated air coils I andthereby effects cooling and dehumidification of the recirculated air.

During winter operation the double throw air switch 15 is set to a Wposition, shown in dotted lines and in this position the thermostatoutlet line 13 is connected to a line 88 which connects with acontroller 8| controlling the admission of fuel to the boiler 45. Inthis position the hygro-' stat outlet line 14 is connected to a line 82leading to the reverse acting diaphragm valve 5|. As the roomtemperature falls the falling air pressure in the thermostat'outletlines 13 and 80 operates the controller 8| to admit more heat to theheater 45. The hygrostat is set to maintain a minimum relative humidityin the room and as the relative humidity in the room falls to thesetting of the hygrostat 'II the rising air pressure in its outlet lines14 and 82 operates the reverse acting diaphragm valve 5| to admit waterfrom the supply line 50, this water passing through the heater 52 andbeing discharged from the nozzle 54 into the air stream.

It will be noted that each of the tubes of the fresh air coil I is fiveruns or passes 63 deep and the recirculation air coil 1 is but threehorizontal runs or passes 8|. deep. Thus, there is a ratio of five tothree in the amount of cooling or heating surface in the fresh air coilsas compared with the recirculation air coils. This ratio is inapproximately correct proportion to the rela-' tive amounts of heatingor cooling surface required to properly heat or cool the air. The freshair requires more heating and cooling than the recirculated air, inbothwinter and summer respectively, because the recirculated air is alwaysat substantially the correct temperature and relative humidity desiredin the room.

Since there are five rows of tubes, in the direction of the air flow,for the fresh air coil and only three for the recirculated air coil, andsince the same velocity for flow of air obtains in both cases, theresistance to the air flow through the two coils l0 and I is in the sameratio, that is, as five is to three. For use in residences and smallstores the amount of fresh air should be enough to equal from one to oneand one-half air changes per hour. In other words, the amount of freshair furnished per hour should bebetween one and one-half times the'cubical content of the space to be heated or cooled. This alsofurnishes the amount of fresh air required for proper ventilation. Thisfresh air amounts to approximately one-quarter of the total volume ofair required to heat or cool the space to be conditioned when the air isfurnished at the number of degrees above or below the room temperaturerequired to maintain correct inside temperature when'heating or coolingis required. It is to be understood that the apparatus is notnecessarily designed to handle 25% fresh air and that the invention isequally applicable for conditions where more or less than 25% of thetotal air handled is fresh air. The restriction to the flow of airthrough either coil, as shown, is approximately in direct proportion tothe number of passes or runs in each of the serpentine tubes throughwhich the air passes to be heated or cooled, and in proportion as thesquare of the air velocity through the same. When hot water rather thansteam is used for heating, the size and number in depth or number ofpasses in each serpentine tube will probably be 4 to 3, that is, fourpasses for the fresh air coil and three passes for the recirculated aircoil, but the-four passes for the fresh air coil will have the samerelative heating or cooling effect as with steam, that is, a 5 to- 3ratio. In other words, with steam, the four passes of the fresh air coilwill have the same amount of surface as five passes where steam is used,as described. This is to give equal or less friction to the flow ofwater through the fresh air coils.

Ratios other than l'to 3 may obtain with relation to the fresh andrecirculated airwith, of course, corresponding change in the relativenumber of coils, although the formulae will remain the same.

The separate functioning of the fresh air coils and recirculated aircoils of this unit assembly is therefore very advantageous in that itpermits a lesser number of rows of tubes and consequently aless amountof cooling or heating surface to meet the small requirements as to heattransfer for the recirculation air coil while at the same time theparallel resistance of the recirculation air coil and the fresh air coilare equal, thus assuring at all times the proper proportions of freshand recirculated air.

When cooling and dehumidifying in the summertime, since the fresh andrecirculated air coils are proportioned so that each of the serpentinetubes of the fresh air coil III has five passes or runs as against threepasses or runs in the serpentine tubes of the recirculated air coil 1,the

fresh air coils will cool and dehumidify the fresh air entering. atapproximately 95 dry bulb and 75 wet bulb to about 65 drybulb and 51 wetbulb, thus removing approximately 11 B. t. u. per pound from the freshair. Under the same outside air conditions, when the system is workingunder full load and the cooling water is therefore also flowing freelythrough the recirculated air coil 1, the inside temperature will beabout 80 dry bulb and 67 wet bulb and the recirculated air will becooled to approximately the same dry and wet bulb temperatures. as'given for the fresh air, thus removing approximately 4 B. t. 11. perpound from the recirculated air. Thus, the fresh air coil- I0, under thefull load conditions given, will remove approximately two andthree-quarter times as much heat per pound from the fresh air as isremoved from the recirculated air by the recirculated air coils 1 andthis is done with only one and two-thirds. times as much coolingsurface. This is due to the fact that the rate of transfer (K value) forthe condensation of moisture from the air is 10 to 12 times as great asfor the removal of sensible heat. Furthermore, since the water goesthrough the fresh air coil I 0 in five passes and countercurrent to theair flow, this continues to betrue even when the flow of cooled water isdecreased through the fresh air coil. The amount of this heat (K value)ofcondensation absorbed per unit of cooling surface per degree oftemperature difference between that of the coil and temperature ofcondensation (dewpoint of the air) is approximately fourteen times (140to 10) as great as that for the absorption of the sensible heat(cooling) of the air. Since in the present system the cooling coils arearranged in multiple passes. (three being shown for the recirculated aircoil and five for the fresh air coil) and-with the cooling mediumflowing counter current to that of the air, it is evident that with aconstant entering temperature of the cooling medium well below thedesired dewpoint of the air leaving the coil, if a large part of theheat absorbed is that of condensation, the cooling water with reducedflow will warm up relatively quick, say, by the time it has completedgoing through the first or entering cooling water pass of the coil,which latter is contacted by the coolest air. Thus, a relatively largeportion of 'the coil is rendered much less effective for cooling the airduring the initial-stages. On account of the relatively high K value ofthis small portion of thecoil containing the initial low temperaturerefrigerant, this small portion of the coil will be very effective incondensing moisture out of the air but will do relatively little coolingon account of the inadequate amount of surface at this low temperature.Also the K 'value decreases with reduced flow of refrigerant through thepipes of the coil and this tends to render. the balance of the coilineflicient for cooling the air. This K value also reduces with regardto effective condensation of moisture out of the air, but when accountis taken of the fact that the transfer rate or K value is about 14 timesas great for absorbing the heat of condensation compared to that of.cooling the air, it is evident that only a relatively small portion ofthe coil is required to do the necessary condensing and that this smallamount of surface is inadequate due to the rapid warming up of thereduced flow of refrigerant to' accomplish much cooling of the air.Thus, the type of coil shown automatically does a relatively greateramount of dehumidifying with relation to cooling of the air,- underreduced flow of refrigerant through the coil. When it is taken intoaccount that the maximum temperature difference betweeniair delivered tothe room and that of the room is never in excess of it is evident thatif the air leaves the coils at say 5 below room temperature or 70 withroom at 75' and the relative humidity on leaving the coil is 60%, itsdew point will be approximately 55.7, and when this air enters the roomand assumes room temperature its relative humidity willbe approximately50% or well within the comfort zone.

on the other hand, if the air leaves the coil at 60* and 80% relativehumidity, it will have a dewpoint of 53.6 and assuming room temperatureof 75, will have a relative humidity of 47%.

When full flow of water obtains through both the fresh air andrecirculated air coils the airpreferably leaves the coils atapproximately 15 below room temperature from both the fresh air coil l8and the recirculated air coil I and since 75% of the air handled isrecirculated air, cutting off the flow of water through the recirculatedair coil, as previously described, eifects 75% of the full coolingcapacity, while still fully cooling and dehumidifying all the fresh airand therefore maintaining correct room temperature and therelativehumidity at not over 50%.

It is also apparent that since so large a percentage (in the conditioncited 75%) of the maintenance of proper room temperature is controlledby the diaphragm valve 82 on the recirculated air coil 1, the diaphragmvalve 36 controlling the flow of water through the fresh air coil Hi,can be dispensed with relying on the circulating pump controller 18 tocontrol the flow of cold water through the fresh air coil l0. Thus, whenthe room temperature drops to the setting of the thermostat thecontroller 18 shuts the circulating pump down. In most cases this lattermethod would be used and only when the percentage of fresh air isrelatively high would the diaphragm valve 36 be required.

In Fig. 2 is shown a modified form of cooler which is suitable for usein connection with the present system. In this cooler melting blocks 85of ice are employed as the refrigerating medium.

These blocks of ice 85 are arranged within a suitably insulated casing86 upon a perforated shelf 81. The return line 88 (which corresponds tothe line 48 in the preferred construction) is provided with a branch 89passing into the housing 86 and this branch line 89 is provided withshower heads 90 which distribute water over the tops of the blocks ofice 85. The cold water collects in the bottom of the body 86 and thelevel is preferably controlled by a float valve 9| which discharges theexcess water. This float valve does not discharge the cold water fromthe bottom of the casing 86 but is connected with the return line 88 soas to discharge the excess water from this line. By this means a savingin refrigeration results since the discharge ofexcesswateristherelatively warm return water rather than refrigeratedice water. The ice water from the bottom of the casing 86 is'withdrawnthrough an outlet line 92 which connects with the inlet of a pump a,this pump delivering the cold water to a pipe 93 which corresponds tothe pipe 2| in thepreferred construction. The circulating pump la isprovided with a controller 18a which corresponds to the controller 18 inthe preferred construction and functions in identically the same manner.

While I have shown and described one form of my invention it will beunderstood that the system is capable of wide variation withoutdeparting from the spirit of my invention and the invention is thereforenot to be construed as being limited to the particular system shown orto the particular temperatures and amounts used by way of example, butis to be accorded the full range of equivalents comprehended by thefollowing claims. it will also be understood that while I have shown apneumatic-control system, an electrical control system is equally ormore adaptable, this being especially true in domestic use where asource of electricity is more convenient than a source of compressedair.

I claim as my invention:

1. In an apparatus for ventilating and conditioning the air in a room orthe like, means for continuously withdrawing air from the room to beconditioned for recirculation to said room means for continuouslywithdrawing outside air, two separate cooling coils one of said coilsbeing deeper in the direction of air flow than the other, and providinga greater resistance to the air flow, the deeper of said coils beingarranged in the path of said outside air and the shallower of said coilsbeing arranged in the path of said recirculated air, means for passing arefrigerating medium through both of said coils at an enteringtemperature below the dewpoint of both of said 2; In an apparatus forventilating and condi-- tioning the air in a room or thelike, means forcontinuously withdrawing air from the room to be conditioned forrecirculation to said room, means for continuously withdrawing outsideair, two separate cooling coils, one of said coils being deeper in thedirection of air flow than the other and having a smaller face areatransverse of the air flow, and providing a greater resistance to theair flow, the deeper of said coils being arranged in the path of saidoutside air and the shallower of said coils being arranged in the pathof said recirculated air, the relative resistances of said coils totheir respective air flows being proportioned to provide the desiredproportions of outside and recirculated air returned to said room, meansfor passing a refrigerating medium through said coils at an enteringtemperature below the dewpoint of both of saidbodies of air andcounter-current to the air flow therethrough, means responsive to thedry bulb temperature in the room for controlling the velocity of saidrefrigerating medium in passing through both, of said coils to adjustboth the cooling and dehumidifying effect thereof and means for mixingthe air after passing said coil.

3. In an apparatus for ventilating and conditioning the air in a room orthe like, means for continuously withdrawing air from the room to beconditioned for recirculation to said room, means for continuouslywithdrawing outside air, two separate cooling coils each of said coolingcoils consisting of a plurality of tubes having serpentine passes, saidtubes, being arranged so that the passing air progressively encountersthe successive passes of each tube, the tubes of one of said coilshaving a greater effective cooling surface than the tubes of the othercoil in approximate proportion as five is to three, and providing agreater resistance to the air flow, the deeper of said coils beingarranged in the path of said outside air and the shallower of said coilsbeing arranged in the path of said recirculated air, means for passing arefrigerating medium through said coils at an entering temperature belowthe dewpoint of both of said bodies of air and countercurrent to the airflow, means responsive to the dry bulb temperature in the room forregulating the velocity of said refrigerating medium in passing throughsaid tubes to adjust both the cooling and dehumidifying effect thereofand means for mixing the air after passing said coils.

4. In an apparatus forventilating and conditioning the air in a room orthe like, means for continuously withdrawing air from the room to beconditioned for recirculation to said room,

means for continuouslywithdrawing outside air,.

and gradually increasing the velocity of the cooling medium passingthrough said fresh air coil on a further rise in room temperature,thereafter admitting said cooling medium to said recirculated air coilon a further rise in room temperature and thereafter increasing thevelocity of said cooling medium through said recirculated air coil onastill further rise in room temperature, said fresh air coil having agreater effective surface in the direction of the airflow than saidrecirculated air coil and said recirculated air coil having a greatereffective face area than said fresh air coil.

5. In an apparatus for ventilating and conditioning the air in a room orthe like, means for withdrawinglair, a coil in the path of said air andhaving inlet and outlet pipes, means for conducting the air from saidcoil to said room, a

heater, a heat controller for said heater, a cooler,

a circulating pump in circuit with said cooler, valve means forselectively connecting said heater and cooler to deliver heating andcooling me dia, respectively, through said pipes to said coils, athermostat responsive to room temperatures, a diaphragm valve inone ofsaid pipes and reverse acting with respect to said thermostat and switchmeans adapted in one position to connect said thermostat outlet linewith said heat controller and in another position to connect saidthermo= stat outlet line withsaid diaphragm valve.

6. In an apparatus for ventilating and conditioning the air in a room orthe like, means for withdrawing air, a coil in the path of said air andhaving inlet and outlet pipes, means for conducting the air from saidcoil to said room, a heater, a heat controller for said heater, acooler, a circulating pump in circuit with said cooler, a

' controller for said pump, valve means for selectively connecting saidheater and cooler to deliver heating and cooling media, respectively,through said pipes to said coils, a thermostat responsive to roomtemperatures, a diaphragm valve in one of said pipes and reverse actingwith respect to said thermostat and switch means adapted in one positionto connect said thermostat outlet line with said heat controller and'inanother position to connect said thermostat outlet line with saiddiaphragm valve and also with the controller for said pump whereby whencooling is not required said pump is shut down.

7. In an apparatus for ventilating and conditioning the air in a room orthe like, means for withdrawing air, a coil in the path of said air andhaving 'inlet and outlet pipes, means for conducting the air from saidcoil to said room, a heater, a heat controller for said heater, acooler, a circulating pump in circuit with said cooler, valve means forselectively connecting said heater and cooler to deliver heating andcooling media, respectively, through said pipes to said coils, athermostat responsive to room temperatures, a hygrostat responsive tothe relative humidity of said room, a humidifying spray adapted todeliver-a spray of water to the air leaving said coil, a diaphragm valvein the water supply line to said humidifying spray and direct actingwith respect to said hygrostat, another said hygrostat outlet line fromsaid direct acting diaphragm valve.

8. In an apparatus for ventilating and conditioning the air in a room orthe like, means for withdrawing air, a coil in the path of said air andhaving inlet and outlet pipes, means for conducting the air from saidcoil to said room, a heater, 9. heat controller for said heater, acooler, a circulating pump in circuit with said cooler, a controller forsaid pump, valve means Iorselectively connecting said heater and coolerto deliver heating and cooling media, respectively, through said pipesto said coils, a thermostat responsive to room temperatures, a humidi-Iying spray adapted to deliver a spray of water to the air leaving saidcoil, means for heating the water to said spray through heat derivedfl'om said heater, a diaphragm valve in the water supply line to saidhumidiiying spray and direct acting with respect to said hygrostat,another diaphragm valve in one or said pipes and reverse acting withrespect to said thermostat and switch means adapted in one position toconnect the thermostat outlet line with said heat controller and thehygrostat outlet line with said direct acting diaphragm valve and inanother position to connect said thermostat outlet line with saidreverse acting diaphragm valve and pump con- .troller and to'disconnectsaid hygrostat outlet line from said direct acting diaphragm valve, theconnection between said thermostat outlet line and said pump controllershutting down the pump when cooling is not required.

- CLAUDE A. BULKELEY.

